My big concern about GIMP 2.8 is that the single-window mode appears to be exactly what was asked for (and nothing more) without any thought as to whether there was a way to reconcile the two user groups' needs... so I think I'll have to continue using WM hackery to force GIMP to behave in a comfortable fashion. (Fake-docked tool palette and image on the left-hand monitor, tool options on the right)

As was said by another poster, single-window mode can be toggled on or off at your own will. You can use whichever mode you prefer. Secondly, it's not only "what was asked for and nothing more": they've actually gone ahead and done lots of work on improving the workflow and even implemented new UI features to make using GIMP more enjoyable.

There was a blogpost a good while back that showed and explained some of the new and improved things, too bad I don't remember where it was :/